About 30 species: Europe through C Asia to the Himalayas and China, also in North America; nine species (two endemic) in China.

Quantitative characters are very variable and reliable qualitative characters are rather few. Plant size varies within wide limits for most species and spikelet size is also very variable. Lemma shape, a stable character, refers to the mature floret when full width has been attained. Other reliable characters for species separation, such as lemma pubescence and awn insertion, require careful observation and a good magnification.